Gaming machines represented by a slot machine are very popular among guests in casinos as a machine that allows a person to enjoy gambling simply, and it has been statistically reported in recent years that revenue by gaming machines account for half or more of the sales in casinos. Early slot machines were simple machines that accepted coins to spin and stop a reel mechanically configured in accordance with a handle operation to determine a win or loss of by a combination of symbols stopped on a single pay line. However, gaming machines in recent years have advanced in sophistication into a variety of gaming machines including mechanical slot machines that drive a physical reel with high precision using a stepping motor controlled by a computer, video slot machines that display a virtual reel on the display connected to a computer, and similar techniques applicable to other casino games. To the manufacturers developing these gaming machines, providing an attractive game that can actively draw in casino guests as players is a critical theme to improving functionality of gaming machines.
In consideration of this background, recent gaming machines configured to increase the interest of the player in the game by staging and processing colorful effects into images displayed on a display unit is becoming more common. For example, Patent Document 1 discloses a gaming machine that provides an expensive prize to the player by having a dragon character displayed on the display unit transport an additional wild symbol.